show diffs in dev releases

.github/workflows/dev_release.yml

@@ -29,6 +29,8 @@ jobs:
 
       - name: Checkout repository
         uses: actions/checkout@v6
+        with:
+          fetch-depth: 0
   
       - name: Install pnpm
         run: npm install -g pnpm
@@ -39,6 +41,13 @@ jobs:
           version=`grep -E '^#define EMSESP_APP_VERSION' ./src/emsesp_version.h | awk -F'"' '{print $2}'`
           echo "VERSION=$version" >> $GITHUB_OUTPUT
 
+      # must run before the release moves the 'latest' tag to this build
+      - name: Find the previous dev release
+        id: previous
+        run: |
+          prev=`git rev-parse -q --verify 'refs/tags/latest^{commit}' || git describe --tags --abbrev=0 --match 'v*'`
+          echo "REF=$prev" >> $GITHUB_OUTPUT
+
       - name: Install PlatformIO
         run: |
           python -m pip install --upgrade pip
@@ -66,12 +75,28 @@ jobs:
         with:
           commit_message: "chore: update generated files for v${{steps.build_info.outputs.VERSION}}"
 
+      # an empty body falls back to the commit list generated by the release action
+      - name: Build the release notes
+        id: notes
+        env:
+          PREV_REF: ${{ steps.previous.outputs.REF }}
+          VERSION: ${{ steps.build_info.outputs.VERSION }}
+        run: |
+          ./scripts/release_notes.sh "$PREV_REF" "$VERSION" > release_notes.md || :
+          cat release_notes.md
+          {
+            echo 'BODY<<__RELEASE_NOTES_EOF__'
+            cat release_notes.md
+            echo '__RELEASE_NOTES_EOF__'
+          } >> $GITHUB_OUTPUT
+
       - name: Create GitHub Release
         id: 'automatic_releases'
         uses: emsesp/action-automatic-releases@v1.0.1
         with:
           repo_token: '${{ secrets.GITHUB_TOKEN }}'
           title: Development Build v${{steps.build_info.outputs.VERSION}}
+          body: ${{ steps.notes.outputs.BODY }}
           automatic_release_tag: 'latest'
           prerelease: true
           files: |